Multitemporal lidar captures heterogeneity in fuel loads and consumption on the Kaibab Plateau
Characterization of physical fuel distributions across heterogeneous landscapes is needed to understand fire behavior, account for smoke emissions, and manage for ecosystem resilience. Remote sensing measurements at various scales inform fuel maps for improved fire and smoke models. Airborne lidar that directly senses variation in vegetation height and density has proven to be especially useful for landscape-scale fuel load and consumption mapping. Here we predicted field-observed fuel loads from airborne lidar and Landsat-derived fire history metrics with random forest (RF) modeling. RF models were then applied across multiple lidar acquisitions (years 2012, 2019, 2020) to create fuel maps across our study area on the Kaibab Plateau in northern Arizona, USA. We estimated consumption across the 2019 Castle and Ikes Fires by subtracting 2020 fuel load maps from 2019 fuel load maps and examined the relationship between mapped surface fuels and years since fire, as recorded in the Monitoring Trends in Burn Severity (MTBS) database.
New types of investments needed to address barriers to scaling up wildfire risk mitigation
Wildfire mitigation is becoming increasingly urgent, but despite the availability of mitigation tools, such as prescribed fire, managed wildfire, and mechanical thinning, the USA has been unable to scale up mitigation. Limited agency capacity, inability to work across jurisdictions, lack of public support, and procedural delays have all been cited as barriers to mitigation. But in the context of limited resources and increasing urgency, how should agencies prioritize investments to address these barriers?
Canopies, the Final Frog-tier: exploring responses of a specialist treefrog to prescribed fire in a pyrogenic ecosystem
Pine flatwoods of the southeastern United States were shaped by frequent fires. Land managers use prescribed fires to control fuels but also to restore historical fire dynamics. Broad outcomes of this practice are well-understood, but impacts on many organisms are still being explored. Frogs, for example, have upland and wetland requirements, limited mobility, and skin susceptible to desiccation. Treefrogs spend most of their lives in uplands away from water. When fire approaches, animals may escape to an unburned area, shelter in place, or be killed by the fire. We examined which of these mechanisms is the prevailing short-term response for a specialist treefrog in a pyrogenic flatwood system.
A novel post-fire method to estimate individual tree crown scorch height and volume using simple RPAS-derived data
An accurate understanding of wildfire impacts is critical to the success of any post-fire management framework. Fire severity maps are typically created from satellite-derived imagery that are capable of mapping fires across large spatial extents, but cannot detect damage to individual trees. In recent years, higher resolution fire severity maps have been created from orthomosaics collected from remotely piloted aerial systems (RPAS). Digital aerial photogrammetric (DAP) point clouds can be derived from these same systems, allowing for spectral and structural features to be collected concurrently. In this note, a methodology was developed to analyze fire impacts within individual trees using these two synergistic data types. The novel methodology presented here uses RPAS-acquired orthomosaics to classify trees based on a binary presence of fire damage. Crown scorch heights and volumes are then extracted from fire-damaged trees using RPAS-acquired DAP point clouds. Such an analysis allows for crown scorch heights and volumes to be estimated across much broader spatial scales than is possible from field data.
Indigenous use of fire in the paramo ecosystem of southern Ecuador: a case study using remote sensing methods and ancestral knowledge of the Kichwa Saraguro people
The Indigenous Kichwa Saraguro people of southern Ecuador have long relied on traditional burning to manage their environment. However, their traditional use of fire in one of the most important ecosystems in southern Ecuador, the herbaceous paramo, is not well known. This lack of knowledge does not allow for the improvement of local regulations related to integrated fire management, which is a shortcoming compared to other regulations applied in South America. In this context, and to understand the impacts of the Indigenous use of fire, a climatic analysis of the area was carried out, generating a historical climograph (period: years 1981-2021) and four annual climographs that were contrasted with a remote sensing study of fire severity over 4 years (years 2018, 2019, 2020, and 2021). In addition, traditional fire use was determined through the application of semi-structured interview questionnaires applied to 61 women and 89 men, whose data were analyzed with the level of information fidelity (LIF), informant consensus factor (ICF), and principal component analysis (PCA). Therefore, in this study, we argue that it is important to incorporate the concepts of (i) wildfire severity and (ii) cultural burning in wildfire policies and regulations in southern Ecuador.
Fuel types misrepresent forest structure and composition in interior British Columbia: a way forward
A clear understanding of the connectivity, structure, and composition of wildland fuels is essential for effective wildfire management. However, fuel typing and mapping are challenging owing to a broad diversity of fuel conditions and their spatial and temporal heterogeneity. In Canada, fuel types and potential fire behavior are characterized using the Fire Behavior Prediction (FBP) System, which uses an association approach to categorize vegetation into 16 fuel types based on stand structure and composition. In British Columbia (BC), provincial and national FBP System fuel type maps are derived from remotely sensed forest inventory data and are widely used for wildfire operations, fuel management, and scientific research. Despite their widespread usage, the accuracy and applicability of these fuel type maps have not been formally assessed. To address this knowledge gap, we quantified the agreement between on-site assessments and provincial and national fuel type maps in interior BC.
Simulating long-term wildfire impacts on boreal forest structure in Central Yakutia, Siberia, since the Last Glacial Maximum
Wildfires are recognized as an important ecological component of larch-dominated boreal forests in eastern Siberia. However, long-term fire-vegetation dynamics in this unique environment are poorly understood. Recent paleoecological research suggests that intensifying fire regimes may induce millennial-scale shifts in forest structure and composition. This may, in turn, result in positive feedback on intensifying wildfires and permafrost degradation, apart from threatening human livelihoods. Most common fire-vegetation models do not explicitly include detailed individual-based tree population dynamics, but a focus on patterns of forest structure emerging from interactions among individual trees may provide a beneficial perspective on the impacts of changing fire regimes in eastern Siberia. To simulate these impacts on forest structure at millennial timescales, we apply the individual-based, spatially explicit vegetation model LAVESI-FIRE, expanded with a new fire module. Satellite-based fire observations along with fieldwork data were used to inform the implementation of wildfire occurrence and adjust model parameters.
Coexisting with wildfire: strengthening collective capacity by changing the status quo
This article is the fuller written version of the invited closing plenary given by the author at the . The article provides a consideration of our capacity to cope, care, and coexist in a fiery world from a social and structural point of view. It focuses on privilege as the root cause of a long and troublesome history within the wildfire profession of not valuing all generational knowledge equally, not treating all cultures with the same respect, not embracing diversity and inclusion, and not affording the same status to all disciplines and voices. The article argues that we can strengthen our collective capacity to coexist with wildfire by embracing local and indigenous fire stewardship practices, by enabling workforce diversity and inclusive leadership culture, and by providing sustainable working conditions for wildland firefighters. To do so requires individual and collective noticing of what is wrong, and everyday action steps towards equity.
Temporal and spatial pattern analysis of escaped prescribed fires in California from 1991 to 2020
Prescribed fires play a critical role in reducing the intensity and severity of future wildfires by systematically and widely consuming accumulated vegetation fuel. While the current probability of prescribed fire escape in the United States stands very low, their consequential impact, particularly the large wildfires they cause, raises substantial concerns. The most direct way of understanding this trade-off between wildfire risk reduction and prescribed fire escapes is to explore patterns in the historical prescribed fire records. This study investigates the spatiotemporal patterns of escaped prescribed fires in California from 1991 to 2020, offering insights for resource managers in developing effective forest management and fuel treatment strategies.
Lightning ignition efficiency in Canadian forests
Lightning-caused fires have a driving influence on Canadian forests, being responsible for approximately half of all wildfires and 90% of the area burned. We created a climatology (2000-2020) of daily lightning efficiency (i.e., the ratio of cloud-to-ground lightning flashes to lightning-caused wildfires that occurred) over the meteorological summer for four ecozones and a subset of British Columbia (BC) ecoprovinces. We estimated lightning efficiency using data from the Canadian Lightning Detection Network and the Canadian National Fire Database. We used the ERA5 reanalysis as inputs for fuel moisture variables (i.e., Fine Fuel Moisture Code (FFMC), Duff Moisture Code (DMC), and Drought Code (DC)) from the Canadian Forest Fire Weather Index (FWI) System, as well as variables relating to the amount of precipitation and lightning flashes. We examined relationships between lightning efficiency, day-of-year, and the above variables using a combination of linear models, Spearman's correlations, and Random Forest (RF) regression.
Wildfire risk perception survey: insights from local communities in Tuscany, Italy
Wildfire is a complex chemical, physical, and sociological phenomenon deeply rooted in the historical relationship between humans and fire. Today the wildfire risk is one of the human challenges. Effective management requires collaboration among multiple stakeholders across different levels. The risk perception and vulnerability at the local community level explain why and how individuals consider certain policies or mitigation behaviors. Thus, wildfire risk fits within the framework of socio-ecological systems.This study focused on four fire-prone areas in Tuscany, Italy, aiming to explore local wildfire risk perception. Risk perception is a social parameter, derived from media habits, memory, history, concerns, and beliefs. Two different surveys were used to consult two groups: experts (e.g., wildfire technicians, policymakers, business activities, and rural associations) and non-experts (e.g., random residents, students, and tourists), then compared to investigate possible gaps. Several questions were asked regarding demographics, relationship with the territory, current management system, relationship with fire and media, risk perception, and others.Results were compared according to the critical area or the type of respondents, and several analyses were conducted to identify weaknesses, strengths, and areas for improvement to raise awareness and lower the risk.
Increasing wildfire frequency decreases carbon storage and leads to regeneration failure in Alaskan boreal forests
The increasing size, severity, and frequency of wildfires is one of the most rapid ways climate warming could alter the structure and function of high-latitude ecosystems. Historically, boreal forests in western North America had fire return intervals (FRI) of 70-130 years, but shortened FRIs are becoming increasingly common under extreme weather conditions. Here, we quantified pre-fire and post-fire C pools and C losses and assessed post-fire seedling regeneration in long (> 70 years), intermediate (30-70 years), and short (< 30 years) FRIs, and triple (three fires in < 70 years) burns. As boreal forests store a significant portion of the global terrestrial carbon (C) pool, understanding the impacts of shortened FRIs on these ecosystems is critical for predicting the global C balance and feedbacks to climate.
